1. Field of the Invention
The present invention relates to a fluid compressor which is assembled in a refrigerating cycle of an air conditioner or refrigerator, and more especially to a compressor accommodating a helical blade in a compressing mechanism.
2. Description of the Related Art
Various kind of refrigerators such as air conditioners for cooling and heating air in a room, refrigerator or showcase, has a refrigeration cycle in which a compressor is accommodated to compress recycling refrigeration medium. Heretofore, for use in these refrigeration cycles, a reciprocating compressor and rotary compressor are well known.
Recently, a new type compressor having a helical blade has been in developed for use in place of reciprocal or rotary type compressors. A feature of this type of compressor is that it has a reduced number of assembled parts, has a simplified compressing mechanism to improve compression efficiency and realize apparatus cost reduction, and also it has merits to reduce noise and/or vibration because there is substantially no eccentric mass in a rotating portion thereof. Such new type compressor is disclosed in U.S. Pat. Nos. 4,871,304, 4,872,820 and 4,875,842.
However, there can be problems in a compressor of the type having mounted therein a helical blade in a compressor mechanism. Thus, in a compressor of this type, the helical blade is designed so as to move freely in the radial direction, in and out along a helical groove formed on the roller piston at a disparity pitch. During operation, this helical blade separates high and low pressure regions respectively and can experience elastic deformation. For this reason, the helical blade is affected by the force caused by the pressure difference between high and low pressure regions. Because of this force, there are several problems by which the helical blade tends to deform, wear, break and/or to reduce durability thereof.